Method of making blocks for printing



E. F. TRETBAR, JR 2,010,905

METHOD OF MAKING BLOCKS FOR PRINTING Aug. 13, 1935.

Filed Aug. 1, 1951 2 Sheets-Sheet l Q lhverv'wr: Edward/1:7 eibag'Jr';

Aug. 13, 1935. E. F. TRETBAR, JR 2,010,905

METHOD OF MAKING BLOCKS FOR PRINTING Filed Aug. 1, 1951 2 Sheets-Sheet 2 1 Patented Aug. 13, 191 3 7 METHOD OF MAKING BLOCKS FOR PRINTING My invention is an improved method of making blocks suitable for printing with viscous printing fluids, such as paint, and providing on such blocks patterns or designs with more accurate 5 outlines and with less tendency of the printing I pins or ribs to break than has been hitherto obtainable with usual processes. i

In accordance with my inventionthe elements of the image, pattern or design to be printed are formed in reliefon the surface of the printing block preferably by outlining the image elements thereon and routering or scooping out the material between the outlines'of adjacent pattern elements, although in some instances the relievo may be obtained by modeling or hammering.

The relief elements are then kerfed to form nar row parallel ribs or pins having between them suitable slits or spaces into which the viscous printing material may partially enter and by which the suction between the printing'surface and printed surface is broken in retracting the block in printing.

Blocks are made in accordance with my process more expeditiously, accurately, with fewer defects, and more economically and provide better registering effects in the printed work.

The characteristics and advantages of my invention will further appear from the following description and the accompanying drawings in illustration thereof.

In the drawing, Fig. 1 shows a fragmentary laminated block having a surface ply of hard H wood, such as maple, suitable for. main the practice of my invention; Fig. 2 shows a block having thereon an outline pattern for imprinting or impressing a desired pattern outline upon the block of Fig. 1; Fig. 3 shows diagrammatically a multiple routering machine which may be provided with routering tools illustrated on an enlarged scale in elevation and end view in Figs. 3a, 3b, 3c and 3d respectively, for intaglioing the block between the'elements of the design; Fig. 4 is a plan View of a block fragment routered out between the design elements; Fig. 5 is a fragmen t-ary sectional view on the line 5-5 of Fig. 4 to show the sunken portions between the relief elements of the design; Fig. 6 shows the block of Fig. 4 after the relievo design has been kerfed to provide narrow parallel printing ribs; Fig. 7

shows a modified method of routering preferably used when the design is to be cross-kerfed to,

form pins; Fig. 8 is a fragmentary sectional view o-n-the line 8-3 of Fig. '7; Fig. 9 is a fragmentary sectional View illustrating a block having its printing surface made by modeling or casting and kerfed; and Fig. 10 illustrates diagrammatically amultiple-h'ead kerfing machine suitable for use in the practice of my invention.

As illustrated in the drawings, the face ply I of the block 2 has outlined thereon any desired design either by drawing or imprinting by means of anoutline edge 3 attached to a base 4. Usually the outline will be repeated a number of times upon the face of the ply I in fixed spaced relation sothat a number of patterns in relief may be cut'simultaneously by suitable tools 5 or 6.

inserted as required in the spindles I carried by the simultaneously movable carriers-8 of a multiple spindle 'routering machine, the spindles and tools being rotated at high speed through suitable driving mechanism 9. The cutting tools preferably have their cutting edges 5a and 6a working always from centre so as to do clean out work in outlining in relief the design A which has been outlined on the face of the ply I. As illustrated in Figs. 4 and5, the routered out portion between the design elements has a depth equal to the intended depths of the kerfs when only-a single series of kerfs are to be used for forming printing ribs. If, however, transverse sets of kerfs are to be used, so as to form pins, the kerfs are out to a less depth as shown in Figs. '7 and 8, and the outline of the pattern B is cut "to the same depth along the edges thereof and surrounded by a further layer C serving as a background reinforcement, such layer 0 being outlined to the usual routering .depth to avoid contact/of the printed material with the body of the block;

When the patterns in relievo have beencompleted they are kerfed by a multiple headker fing machine havinghigh speed rotary saws l0 and which cut in the reliefs narrow slits II parallel with one another and leaving between them printing ribs l2, as shown in Fig. 6.

For certain kinds of work it is preferable to use spaced pins of various shapes instead of spaced ribs, and in such event the relief pattern is kerfed in transverse directions at desired angles to form slits l3 and l4 having between them printing pins l5.

' Instead of carving the reliefs from a solid block, the reliefs may be cast of metal or other mouldable material in suitable outline upon a base as shown in Fig. 9. In this adaptation of the invention, there is moulded, by casting or otherwise, a base l6 having the relievo design elements 7 ll moulded thereon and kerfed to form the slits l8 spacing the printing ribs IS. The base l6 may be fastened in any suitatble manner such as with tacks 20 upon a block 2| having a tablature 22 having the general form of the design elements.

Having described my invention, I claim:- 1. In a method of making printing blocks, the

steps which consist in intaglioing a block to' form layers of difierent elevations, the higher of said layers outlining pattern elements in relief, and kerfing said pattern elements to form transverse slits extending to approximately the level of the'lrigher of the intaglio layers.

2. 'Ilie'methodof making printing blocks which comprises intaglioing a block to form layers of difierent elevations including a higher layer out- 

